[英].Net Core Entity Framework .Include Eager load does not load entity
[英]ASP NET Core crashing when using eager load with Entity Framework
我有一个简单的电话:
public IActionResult GetApplications()
{
var result = context.Applications.Include(a=> a.AplicantCompany)
.Include(c=>c.CreditorCompany)
.ToList();
return Ok(result);
}
哪个返回:
{"result":[{"context":null,"applicationId":1003,"aplicantCompany":{"id":1,"creditCompid":12344,"name":"Kibon","industry":"ice cream","address":"RaiboW street","city":"Rio de Janeiro","province":"Rio de Janeiro","country":"Brazil","postalCode":"9034-394","style":"modern","yearsStablished":100,"numEmployees":600,"salesAnnual":"12343434","taxId":323,"functionOfScore":12,"dateCreated":"2018-08-09T14:14:38.3325627"},"applicantCompanyID":1,"creditRequested":33333,"creditTerm":1,"processStatus":1,"recommendation":1,"approved":true,"creditApproved":1200000,"dateCreated":"2018-08-09T14:18:32.900369","dateProcessed":"2018-12-12T00:00:00","creditorCompanyId":1,"creditorCompany":{"creditorCompanyId":1,"name":"IBM","address":"boulevard of dreams","city":"Toronto","province":"ON","country":"Canada","postalCode":"M1t 2t5","revenue":12343,"riskPreference":23,"creditLimit":123,"portofolioScore":5.5,"userName":"Ronald","password":"1234","dateCreated":"2018-08-09T12:09:18.0977008","applications":[
由于某种原因,实体在获取其余数据之前就中断了。
当我尝试使用属性时:
[HttpGet("/api/applications")]
public IActionResult GetApplications()
{
var result = context.Applications.Include(a=> a.AplicantCompany.Name)
.Include(c=>c.CreditorCompany.Name)
.ToListAsync();
return Ok(result);
}
我什么也没收到。 有人知道发生了什么吗?
注意:我现在收到此错误:
System.InvalidOperationException:'属性'Name'不是实体类型'ApplicantCompany'的导航属性。 “ include(string)”方法只能与“。”一起使用。 导航属性名称的分隔列表。”
但是财产存在...
您对ToListAsync()
调用返回一个Task
,到您从该方法返回时,该Task
可能尚未完成执行。 最好的解决方案是使方法异步,如下所示:
public async Task<IActionResult> GetApplications()
{
var result = await context.Applications.Include(a=> a.AplicantCompany)
.Include(c=>c.CreditorCompany)
.ToListAsync();
return Ok(result);
}
这些更改将导致该方法在继续return
语句之前等待所有结果,同时允许其他请求在等待数据时运行。
第二种情况可能不起作用,因为EF希望使用Include
加载整个实体。 如果要加载AplicantCompany
引用的另一个实体,则可以使用
.Include(a => a.AplicantCompany).ThenInclude(c => c.Entity)
实际上,根据此答案 ,您可能可以做到(我没有尝试过):
var result = await context.Applications.Select(a => new {
Application = a,
CreditorCompany = a.CreditorCompany.Name,
ApplicantCompany = a.AplicantCompany.Name}).ToListAsync();
首先,
Include()
方法用于加载相关数据,而不是相关数据的属性。 这意味着,要在实体“应用程序”上加载相关的AplicantCompany和CreditorCompany的name属性,您的第一个查询是正确的。 它将包括两个相关实体的名称属性
var result = context.Applications.Include(a=> a.AplicantCompany)
.Include(c=>c.CreditorCompany)
.ToList();
其次,如果您使用的是异步方法ToListAsync(),则需要等待任务
[HttpGet("/api/applications")]
public async Task<IActionResult> GetApplications()
{
var result = await context.Applications.Include(a=> a.AplicantCompany)
.Include(c=>c.CreditorCompany)
.ToListAsync();
return Ok(result);
}
您对ToListAsync
调用是异步的; 但是调用和方法本身是同步的。 更改为ToList()
或(更好)使其他所有内容也异步
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